


She's Out Of This World

by kittenofdoomage



Category: Supernatural
Genre: Case, Danger, F/M, Female Reader, Horror, Hunting, Mermaid!Reader, Mermaids, Reader Insert, Sex, Smut, four parter, mermaid au, request, sam x reader - Freeform, smut to come
Language: English
Status: Completed
Published: 2016-08-18
Updated: 2016-08-25
Packaged: 2018-08-09 15:46:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 14,424
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7807774
Author URL: https://archiveofourown.org/users/kittenofdoomage/pseuds/kittenofdoomage
Summary: <blockquote class="userstuff">
              <p>Anon request: Oooohhhh Requests!!! Yeep!!! Could you do a SamxMermaid!Reader one, where the boys are hunting an aquatic monster (or maybe even another mermaid) and Sam is torn between trusting her or suspecting her once he discovers what she is? Smut maybe? Thanks!!! :D</p>
            </blockquote>





	1. Chapter 1

‘Smell that fresh sea air, Sammy.’

Sam smiled as Dean threw his arms wide, inhaling deeply as he stood beside the Impala. They’d parked up on Beach Street, near Ghiradelli’s, and the smell of chocolate was strong in the air, making even his healthy tastebuds water.

‘Technically it’s the ocean,’ he pointed out, as Dean sent him a filthy look. Sam chuckled, grabbing his duffel from the car. They’d booked into a hotel on the seafront, close to Fisherman’s Wharf, where the case had lead them. Normally, big city hunts weren’t their thing, but in this case, Dean had insisted, mainly because he hadn’t been to San Fran since he was younger, and he wasn’t gonna deny himself all the delicious treats on offer.

‘Maybe we should do the tandem bike ride over the bridge.’ The elder Winchester suggested, picking his bag up from Baby’s backseat, patting her roof gently. Sam raised an eyebrow in his brother’s direction, before shaking his head. ‘What?’ Dean exclaimed, shrugging at him.

‘You’re always wondering why people think we’re gay,’ Sam pointed out, directing a finger at his brother. ‘It’s because you say shit like that.’

Dean grinned. ‘Yeah, but chicks dig gay guys, right?’

‘Doesn’t work if you’re not gay, Dean. And that’s kinda homophobic.’ Sam held open the hotel door, waiting for Dean to follow him through.

‘Point taken. We could do a regular bike ride though. Like tourist crap.’ Dean watched his brother’s face change, and smiled widely. ‘Okay, no bike ride.’

‘I might go up to the cable car museum. That looks interesting.’ Sam laughed as Dean rolled his eyes, ignoring his response in favour of approaching the desk. They checked in quickly, heading up to their twin room, and Sam immediately threw himself down onto his bed and stretched out. ‘This is way more comfortable than the last motel.’

Dean eyed him, dropping his bag onto his bed and pulling his gun from the back of his pants. ‘Well, no time to get cozy, Sammy. We’ve got six missing people, one corpse and a whole lot of witnesses to check out. Get your fed on.’

Sam sighed, making a mental note to at least have five minutes to enjoy some clam chowder once they got down to Pier 39.

*****

‘And you say you didn’t see anything?’ Sam held his notebook up, scribbling away as he spoke to the pier worker, who leaned on his broom heavily.

‘No way, man. There was a scuffle, I heard that, then a splash, but when I went out there the woman had disappeared. Her shopping was still there and then I saw one of her shoes floating in the drink, but nothing else, man, I swear.’

Sam gave the man a tight lipped smile, before thanking him and moving on. It was getting dark along the pier and the shops were closing, but the restaurants and bars remained open, with people laughing and drinking all around. Dean was leaning against the front barrier of a restaurant called Pier Market, obviously flirting with, and not questioning, the young lady who was unsuccessfully seating people in the busy venue.

Dean stood straight as he glimpsed his brother approaching, clearing his throat as he pretended to have been doing some work. ‘So, you, er, you haven’t heard anything about these disappearances?’

The girl, Tina, upon closer inspection of her name tag, looked confused at the change of subject, and she frowned. ‘Missy Peterson was one of the girls that got took,’ she said, her expression turning sad. ‘She worked here.’

Sam perked up as Dean tried to hide his cheeky grin, his ruse working without an inch of effort. ‘And Missy – did she have any enemies you were aware of?’

Tina shook her head. ‘Missy was a sweetheart. She was only here a month, didn’t know many people in town.’

‘Any family? Maybe boyfriends?’

Another shake of the head, and Sam frowned. ‘Her mom lived back out east, but they didn’t talk. And I never saw her with a guy. She used to talk to Walt, but that’s about it.’

‘Walt?’ Sam asked, pulling out his notebook.

‘Walt’s the old busker down the other side of Autographica. He sings a lot of old songs, like Rolling Stone stuff, plays guitar. Missy liked his music, said he reminded her of her pops. But he’s a harmless old guy. Everyone knows him.’

Sam smiled, scribbling down the location, before sliding his notebook back into his pocket. ‘Thank you, Tina. Sorry to disturb you.’ Tina beamed, turning away as a group of rowdy young men approached. Dean pouted as Sam practically dragged him away from the fence, and the younger hunter shook his head at his behaviour. ‘I asked you to gather witness accounts, not flirt with a girl twenty years too young for you.’

‘I’m offended.’ Dean put a hand on his heart.

‘Keep it up,’ Sam ignored his brother’s dramatic act as they weaved through the thinning crowds. The sun was almost fully down now, and the people were leaving for the night, but Sam didn’t have any intention of abandoning the pier until he had more information. As they skirted round the back of a bar, he glanced to his left, seeing a bench with a viewing spot, and a pang of pain hit him straight in the chest.

Ten years ago, probably more by now, he’d brought Jess here for the weekend, and they’d spent hours just wandering, shopping, enjoying the culture and the sights. Now he was here to hunt a monster, not that he would change it now. It hurt to remember her, and always would, but with the good he’d done for the world, he couldn’t hate his life, not entirely.

The only thing he hated was how alone he felt when he remembered her. Dean was his brother, and that company was almost enough, but there was a hole in Sam’s heart he didn’t think would ever be filled.

‘Think that’s our guy?’ Dean’s voice dragged Sam back to the present, and he looked in the direction Dean was pointing. The old man was sitting on a pile of threadbare and filthy blankets, a sad looking old hound by his side as he played on an acoustic guitar that had seen better days. He was playing a very slow version of “Paint It Black” and by the look on Dean’s face, it wasn’t a bad rendition. ‘Guy likes some decent music, I kinda hope he’s not evil.’

Sam smiled, clapping Dean on the back as he walked towards Walt. A lady moved past the old man, dropping some coins into his little basket, and Walt dipped his head with a toothy smile at the lady.

‘Hey.’ Sam said, crouching down and reaching out to pet the man’s dog. Walt kept playing, smiling at them, as Dean tapped along to the song. The dog looked up at Sam with big eyes, obviously enjoying the attention. ‘I’m Agent Sparrow, that’s Agent Gibbs.’ He gestured to Dean as Walt nodded again. ‘We’re investigating some disappearances from the Pier, and we were told you knew one of the missing girls – Missy Peterson?’

Walt stopped playing, sadness filling his old eyes. ‘Missy…lovely girl. Always had a coffee and a donut for me.’ He shook his head, before looking down at the old dog, who whimpered and pressed his head into his master’s leg. ‘Wilfred always loved seeing her.’

‘Walt and Wilfred?’ Dean’s voice was a little too loud, but the old man didn’t seem to hear it. Sam sent his brother a glare for good measure, before turning his attention back to Walt.

‘Do you know anything about what happened to her?’

‘Ocean’s a terrible place.’ Walt’s voice was low and gravelly, his fingers absently drifting over the strings of the battered guitar, making a slight noise as they did so. ‘Sometimes, the spirits get angry. Sometimes, they want something from us, and we don’t give it. So they take it, and they take it without mercy.’ His eyes were glazed over, like he couldn’t even see Sam. ‘I wish they hadn’t taken Missy. They took her, and they stole her future.’

‘Who took her?’ Dean asked, leaning down.

‘Can I help you, gentlemen?’ A voice made both Winchesters stand straight, as Walt was seemingly knocked from his trance. A rather overweight police officer stood in front of them, his arms folded over his chest. ‘You harassing Walt there? He ain’t doing any harm.’

‘No, sir.’ Sam smiled, pulling his fake identification out of his pocket to show the officer. ‘Just asking a few routine questions about the disappearances around here.’

‘Drunks falling into the water.’ The officer shrugged. ‘Happens more often than people think.’

Dean glanced at Sam, before narrowing his eyes at the officer. ‘You’re telling me, that a twelve year old girl was drunk, and fell over the side of the pier?’ The officer shrugged again, looking thoroughly disinterested. ‘Doesn’t that strike you as a little strange?’

‘No complaints from the public.’ The officer sighed. ‘Look, you gentlemen can look into it all you. Drunks, addicts – they go missing in this city all the time. The kid, yeah it was sad, but she was a runaway from a foster home. Unfortunately, no one is missing her.’

‘That’s not the point,’ Sam started, only to be interrupted.

‘I’ve got real problems to look into. Keep out of trouble, or I’ll be hauling you down the precinct.’ The officer turned, walking away with a shake of his head as Dean and Sam looked at each other in surprise.

Walt chuckled from his spot on the floor. ‘He doesn’t see. They don’t see, so they don’t care. Ocean will take him too, maybe. We’d all be thankful for it.’

Sam looked down at Walt, frowning. ‘You said the ocean took these people?’

The old man grinned widely, showing off the gaps between his teeth again. ‘What, y’all think there’s just fish down there. Trust me, son, there’s more than just a few sea lions that make thirty-nine their home.’

*****

‘Are you seriously going to hang out here, all night?’ Dean watched as Sam got comfortable sitting on the bench. It was nearly midnight and the bars were closing down, the people drifting away from the pier. Walt had gone from his spot, muttering about moving further inland for safety. They’d gotten as much as they could out of the old man, but Dean wasn’t happy with the information. ‘You realise that old guy is probably crazy, right? He was talking about people living in the sea, Sam.’

‘Ocean.’ Sam corrected, automatically, glancing behind him as the sea lions made more noise. ‘Dean, you can either quit bitching and stay here tonight with me, or you can go back to the motel room and do some research.’

‘Can I pick the third option?’ Dean grinned, and Sam sighed heavily. ‘Come on, man. There’s so many bars here.’

‘It’s also gone midnight. You think you can score, then go score. I’ll wait here and do the actual work.’

‘You’re such a square,’ Dean groaned. ‘I’ll go see what I can dig up on The Little Mermaid, yeah? But for the record, this is bullshit.’

‘Noted.’ Sam smiled. ‘Bring me a coffee in the morning.’

‘Try not to freeze to death,’ Dean called, walking away and flipping his brother off as he did. Sam laughed, before casting his eyes out to the horizon. There was a mist settling over the sea, and he could barely see Alcatraz, let along the Golden Gate Bridge. The noise from the bars started to dwindle, and the sea lions quietened down, only the odd splash reaching his ears. Soon, it was quiet, and the wind picked up a little, prompting Sam to pull his coat closer around his body.

Hours trickled by, and Sam struggled to keep his eyes open, his head drooping as he desperately tried to stay awake. As it drew closer to three in the morning, he contemplated going back to the motel, and as he stood to leave, a noise caught his attention. Footsteps, on the pier, and he quickly looked around, ducking behind a low wall to see who was down here at such a late hour.

When the figure emerged, bathed in dim moonlight filtering through the hazy sky, his jaw dropped, and he almost blew his own cover. The woman was almost naked, with only the flimsiest of clothes covering her modesty, and her hair was long and wild, running down her back with obvious tangles. She glanced in his direction, and he ducked down behind the wall, grunting in discomfort as he tried to squeeze his large size into a small space.

‘I can see you.’ The woman crooned, a smile on her face. ‘You shouldn’t be here. It’s not safe.’

Sam pulled his head up, making eye contact with the woman as he stood, flexing out his cramped muscles. ‘It’s not safe for you either, ma’am.’

‘Do I look like a ma’am to you?’ She grinned, almost swaying as she watched him. ‘And it’s plenty safe for me. I’m not the one with “prey” stamped on my forehead.’

‘You know what’s been taking people from this pier?’ Sam asked, stepping towards her. She almost jumped back, frowning at him.

‘The ocean.’

‘Why wouldn’t it want you?’ He questioned, and she smiled, turning away to climb on the fence. ‘Whoa, maybe you should get down.’ He wondered if she was a little…unwell, as she walked along the fence edge like a goddamn  gymnast. ‘That’s probably not safe.’

‘I’m fine.’ The woman replied, looking down at him, before blowing him a kiss. ‘But you should leave.’

‘Hey!’ Flashlights hit the pair of them, and the woman yelped in shock, losing her concentration, her balance going with it, and she fell backwards, landing in the water with a hard splash. Sam yelled in horror, barely sparing a glance for the police officers running down the pier towards him. ‘Hey!’ He ignored the shouts, ripping his jacket off, kicking his shoes away and climbing up onto the fence, throwing himself into the water without a second thought.

The ocean was freezing, and he went under for a second, seeing the flashlights hit the water above him. He used his arms to propel himself upwards, unable to hear whatever the officers were yelling over the roar of the water in his ears. Looking around, he saw no sign of the girl, and ducked under again, trying to see her.

‘What the hell are you doing?’ A hissed voice from behind him make him spin in the water, and he came face to face with the woman, shock making his eyes go wide. He opened his mouth, forgetting he couldn’t breathe, and almost choked as she grabbed him and pulled him under the pier. His head breached the surface, and he gasped for air as she scowled at him.

‘You fell!’ Sam coughed, still staring at her in amazement. ‘You fell in the water and I…I just…’

‘I don’t need saving.’ The woman retorted, apparently really pissed about the situation and Sam drew back, glancing upwards as the officers stomped away.

‘You must be a really good swimmer.’ He pointed out, and the woman laughed loudly, before turning around and diving under the water. As her back disappeared, replaced  with a long fanned out tail, sparkling with different colours. Sam’s eyes widened and he backed away, his arms flailing in the water to propel himself towards where the officers could see him. The woman burst out of the water behind him, coming to a stop and placing her hands on his shoulders. ‘You…you…’

‘Mermaid, yes. Get it out of your system, sweetheart.’ She grinned, turning him around. ‘Now, how about we get you out of this water before you catch hypothermia. I’ll have to take you around the sea lions – they’re not a fan of intruders in the water.’ Sam didn’t object as he took her hand, noticing her fingers were slightly webbed at the joints. She pulled him under the pier, weaving in and out of the posts and around the boats moored nearby, until they came to a small bit of beach. As he climbed up onto the sand, he turned, seeing her sat in the shallows, watching him.

‘Do you have a name?’ Sam asked.

‘Yes. Doesn’t everyone?’ She grinned.

‘Are you going to tell me it?’

She shrugged. ‘It’s unlikely. But not impossible.’

‘I’m Sam.’

‘Good for you.’ She sassed, and he narrowed his eyes. ‘Sam, stay out of the water. Leave this to me, yeah? I don’t need a hunter helping me, you’ll just get hurt.’

‘You know what’s taking the people?’ He called, as she made to swim away.

‘I told you, it’s the ocean.’ She replied, waving as she swam backwards into deeper water, making a show of letting her tail slap at the surface. ‘See you around, Sam.’ With a flourish, she disappeared under the water, and Sam watched for a few moments, hoping she’d resurface. When she didn’t, he stood up in disappointment, groaning as he realised he’d left his shoes and jacket on the pier.


	2. Pt 2

 

Dean’s expression was unreadable, and Sam waited for his brother’s response as he dried his hair off. He’d managed to get back from the beach with only a hole in his soak, and a slightly bruised ego, and was surprised to find Dean still up when he’d rolled back in around the four am mark.

‘Let me get this straight…’ Dean took a breath and Sam simply sat, and waited. ‘She turns up, almost nude, on the pier, falls into the water and you...dive straight in after her?’

‘Yep.’ Sam popped the “p” at the end of his answer, and Dean scrubbed a hand over his face.

‘And she had a tail. An honest to God tail?’

‘I swear it.’

Silence fell over the motel room for a moment as Dean mulled the information he’d been given six times already, unable to accept the reality of what his brother was telling him. ‘She had a friggin’ tail?!’

Sam rolled his eyes, balling up the wet towel and throwing it across the room. It landed with a soggy thump in the middle of a burgeoning sunny patch. ‘Yes, Dean, a tail. I wasn’t drug, or high, or hallucinating, I jumped in to save her and she didn’t need it.’

‘Don’t mock me, Sam! You’re the one who came home and said he’d had a close encounter with the little friggin’ mermaid!’ Dean shook his head. ‘This is insane. Mermaids. They’re real?’

‘Merfolk would probably be the more politically correct -’ Sam’s correction was interrupted as Dean exploded.

‘Politically correct?! Sam, they’re  _ fish _ .’

‘Technically, they’re human-fish hybrids. According to the lore -’

‘Lore?’ Dean asked, eyes wide. ‘There’s  _ lore _ for this crazy horseshit?’

Sam heaved a sigh, and nodded. ‘Look, you found lore while I was out, right? On what our mysterious creature could be?’

Dean narrowed his eyes. ‘You  _ found _ the mysterious sea creature, Sam. And she sassed you, then warned you to stay away. Clearly, we know who is taking these people.’

The younger Winchester’s mouth was a thin line as he contemplated his brother’s words. ‘I don’t think it’s her. And before you start, I’m not blinded by monsters. I’m just saying I don’t get a evil vibe off her.’

‘You didn’t get an evil vibe off Ruby.’ Dean pointed out, rendering Sam mute, his eyes almost glowing with irritation. ‘She’s not human, Sam. You gotta see that. We can’t decide anything until we’ve got more information. I’m not saying we rush off and white whale her, but we gotta know what’s doing this, and put a stop to it.’

‘She said she knew.’ Sam muttered, picking at the flaked plastic cover on the table. ‘She said the same thing Walt did - that the ocean was behind it.’ Dean went quiet for a moment, before leaning over and passing Sam a book. ‘What’s this?’

‘The lore I found. I searched everything to do with sea monsters, but most of them are myths. This one however...it showed up because it happened before. Except the last time it happened, it stopped mysteriously and no one knew why.’

Sam took the book, looking at the thick paragraphs of text. ‘It’s changed places?’

‘Pier 39 has only been there since seventy eight. The last disappearance kept happening off of Alcatraz. Workers went missing from boats. Vessels came back into dock with no one on them.’ Dean pointed at a page. ‘One guy says he was sleeping in his cabin, and came up to find his other three crewmates missing. Only one thing links all the victims.’

‘They were all under forty.’ Sam muttered, tracing his finger down the page. ‘It’s not much to go on. This seems random.’

Dean shrugged. ‘There’s no other lore. I checked everything, and the only thing I could find on the internet was all about sea lions.’ The elder Winchester sighed, standing up from his seat. ‘Anyway, I’m gonna hit the hay. We can start fresh with this tomorrow, maybe see if we can find your strange little friend whilst we’re at it.’

‘Maybe.’ Sam didn’t look up as Dean stripped down to his boxers and climbed into bed. Within moments, his brother was snoring like a freight train, and Sam shut the book, deciding it was probably a good idea to get some sleep.

Only problem was, his dreams kept being filled with the flash of rainbow coloured scales.

*****

**_Reader’s POV_ **

They still hadn’t left. You thought you’d gotten the message across to the taller one, but he hadn’t taken the hin. Of course, you’d put yourself in a stupid position by revealing yourself in the first place, and if those stupid guards hadn’t shown up, you might have been able to get him to leave without waving your tail all up in his face.

You’d made an effort to be on dry land before the sun was fully up, drying yourself off on a quiet corner of the pier, before sneaking into through the back door of a clothing shop to steal a pair of shorts and a t-shirt. As people starting piling onto the pier, you slunk around the back, heading away from the sea and into the bustling tourist section of Fisherman’s Wharf.

It wasn’t difficult to locate the hunters - they might have been the sorest thumbs in San Fran, and the shorter of the two had an appetite that was voracious at worst. As you spotted them wolfing food down in a corner cafe, you decided that surprise was your best element here. You quickly pushed through the crowd and into the cafe, ignoring the call from the waitress to wait to be seated.

‘It’s okay, I’m with them,’ you called back, sliding into the seat next to Sam, who stared at you with his jaw in his breakfast, as Dean’s eyes bulged out of his head. ‘Hey.’

‘You’re...you’re…’ The stutters Dean was making were kind of adorable.

‘Yep, I am.’ You grinned widely, stealing a piece of watermelon from Sam’s plate. ‘Mmm, love this stuff.’

‘You’re a mermaid.’ Dean’s voice was a hiss as you chewed on the fruit and rolled your eyes. ‘What are you doing in here?’

‘Firstly, you can call me Y/N.’ You glanced at Sam. ‘I said it was unlikely, not impossible. And secondly, you clearly aren’t going to take the hint that I can deal with this myself, so I’m enlisting your help instead.’

Dean narrowed his eyes, swallowing his mouthful of pancake, and pointing his fork at you. ‘Now, listen here lady, we don’t need your help. For all we know, you’re behind all this.’

You raised an eyebrow, still chewing the watermelon. Slowly, you finished your mouthful and set the fruit back on Sam’s plate. He remained quiet, almost like he was studying you. ‘I’m not. Dean, is it? I was watching you yesterday. Not very stealthy, that’s for sure.’

‘That’s...I….shut up,’ he growled and you sniggered.

‘Look, I know exactly what is causing all of this. You’ve got what, seven people missing?’

‘Six. A corpse turned up two days ago. The first person to go missing.’ Sam had put his breakfast utensils down and was watching you thoughtfully.

‘I thought as much. That means she’s started feeding, and you don’t have much time before she decides seven isn’t enough. Usually it would be, but this time...something’s got her pissed, and I don’t think she’s gonna go back to sleep once she’s full.’ You picked up the watermelon again, taking another bite. ‘So, how about you boys finish your breakfasts, and I’ll give you all the gritty details, yeah?’

Both men nodded, and you smiled, finishing off the watermelon as the Winchesters finished, and paid their bill. You snagged an apple on the way out, taking a healthy bite as you followed them out the door.

‘Where are we going?’ Sam asked, pausing on the sidewalk.

You pointed to the Wharf, where a sign could be seen saying “boats for rent”. ‘We’re going out to sea.’

Dean looked at you sharply, before glancing to Sam, who shrugged. ‘Out to sea? On a boat.’

‘What else did you expect to go on, a banana?’ You scoffed, heading towards the seafront, quickly locating a gentleman with a generously sized boat he was more than happy to take you out on. Sam paid the man the fee and within moments, all three of you were sat comfortable away from the boat owner, watching the piers become smaller and smaller. ‘Right, now we’re somewhere a little less public....’

‘You said “she”,’ Dean asked, leaning forward. ‘Who’s she?’

‘Her name is Sedna,’ you replied, looking around. ‘There’s a lot of myth surrounding her, but I know one thing - she’s been around for centuries, and she hasn’t always been in San Francisco. She came here a long time ago, but she’s only fed twice in these waters.’

‘How do you know this?’

You shrugged. ‘We’ve had to stop her before.’

‘We?’ Dean’s question was laced with concern, and it rubbed you the wrong way as you regarded him.

‘Yes, we. My mother, my father, my brothers. We, as in  _ we _ . Plural.’ You sat back, lacing your fingers together on your lap as you looked away from them and out to sea. The bridge was not far now, and you could see the telltale shadow of porpoises jumping across the water. ‘At least, it was. Sedna killed most of us because we would not worship her. She believes herself a goddess, but she’s just another monster.’

Sam sat up straight, one hand bracing his huge frame against the side of the boat as it bounced on the waves. ‘And she’s who is taking people.’

‘She feeds on them. Every so often, and there’s no set time with her, she’ll come up and she takes seven. Seven humans from the land. She feeds slowly, so there is still time.’ You turned, shouting out to the boat owner. ‘Can you turn towards that island there?’

‘Sure thing!’ The driver yelled back, and the boat began to turn. Dean was looking a little green around the gills, and you smirked.

‘You feeling okay?’

Dean scowled. ‘I’m fine. Continue.’

‘Sedna doesn’t just eat people. She eats their futures. The younger they are, the better, but she can...I don’t know,  _ sense _ if someone is capable of doing something great. Or even if they’re going to live a long and productive life. She can take that away, every opportunity, every chance, everything, and it sustains her. The greater the potential, the longer it sates her.’ You watched both hunters closely, your eyes landing on Sam, locking with his hazel gaze. ‘So, you see what I’m saying here? We’ve got a limited window to save the ones she’s already got, and we’ve gotta hope she doesn’t decide to take more.’

Dean held a hand up. ‘How are we supposed to stop a sea goddess?’

You looked down, blushing. ‘I’m still working on that. I know there’s a weapon made with fresh water that is supposed to harm her but...well, it’s hard to keep books in a good condition when your apartment is way past sea “adjacent”.’ You scowled.

‘And you thought you could handle this by yourself?’ The elder brother scoffed, and Sam kicked his shin. ‘What? She’s telling us to back off, when she hasn’t got a clue.’

‘What, and you’re an expert on this bay? I’ve lived here my whole life, and I know exactly where she is.’ You folded your arms over your chest, your scowl deepening. ‘We’ve got a very limited window here to save these people. So you in, or shall I ask this guy to turn the boat around. I swim faster alone.’

Sam glanced at Dean, who rolled his eyes and nodded, looking out over the bay. Sam sighed, looking back to you and nodding, leaning back against the edge of the boat. ‘You said you know where she is.’

‘Sedna lives in a cave system just north of the bridge. It’s underwater, some of it is accessible from land during low tide but…’

‘It may have escaped your notice,’ Dean started, ignoring his brother’s warning look. ‘But we are humans. We can’t just grow a tail and go for a quick dip.’

You smiled broadly, eyes sparkling as you locked eyes with Sam again. ‘What if you could?’

Both hunters froze at your words, Dean looking confused and Sam looking more than a little intrigued. ‘You know a way? Is there like, magic or something?’ The longer haired of the two asked, leaning towards you. It was difficult to avoid his scent, like fresh leaves and the deodorant he favoured. 

After a few seconds, you shook your head, laughing a little, seeing Dean relax. ‘No. I can’t turn you into something you’re not. It’s strictly a species only ability. But…I can take one of you with me. The oxygen in my lungs is more enriched - helps having four of them -’ You could practically see the amazement in Sam’s eyes and somehow knew you’d be facing a lot of questions later. ‘So I can help you breathe. It involves some close contact though.’

Dean narrowed his eyes. ‘How close?’

‘Basically underwater CPR without the chest compressions. You won’t be able to talk to me, but I can keep you alive down there.’

‘Are you talking...like Splash type kissing?’ Dean’s mouth dropped open as you nodded. Sam raised an eyebrow, looking at his brother like he was crazy. ‘You know, the film. Daryl Hannah and Tom Hanks. She’s a mermaid, he’s a clueless human...am I the only one who saw this film?’

‘No, I’ve seen it.’ You shrugged. ‘Just didn’t think much of it.’

Sam glanced at Dean, before looking back to you. ‘I’ll do it. I’m a better swimmer than Dean.’

‘Are not.’ Dean protested, before Sam punched him in the arm and gave him a stern look. The elder brother glared back, before he caught onto Sam’s meaning and you stifled a giggle at his behaviour. You would prefer if it were Sam you had to engage in liplock with - Dean didn’t seem to be at all able to look past the “different species” barrier. ‘Whatever, I’ll stay on the boat.’

‘You need to be careful. There’s rumours of Sedna’s power, but I’ve never seen it first hand. Or her, for that matter. I don’t know what she looks like.’ You slumped down a little. ‘I know she can control the water. That’s how she takes her victims.’

Dean huffed as the boat moved under the bridge, and he looked up at the grand metal structure. ‘At least we can say we did the bridge trip.’ He shrugged. You smiled, before standing up and heading up to where the driver stood. Out of hearing, Dean leaned into his brother, lowering his voice.

‘You think we can trust her?’

Sam’s eyes landed on your denim short clad rear and he nodded. ‘Yeah, Dean, I do. She seems genuine and she’s smart. I don’t think she means us any harm. She’s working with us, isn’t she?’

Dean’s mouth set into a thin line. ‘You think she’s pretty.’

A red blush covered the younger Winchester’s cheeks as he blustered out a reply. ‘That’s not the point.’

‘You seemed awfully eager to share a liplock with her for the sake of breathing.’

‘And?’

Dean sat up straight as you turned and came back over, smiling widely. ‘We’re almost there. Sam, I hate to say it, but you might not wanna be wearing all those layers for swimming.’

Sam swallowed, hard, as Dean sniggered. ‘Right. Gotcha. I’ll er...I can wear my boxers though, right?’

‘Should be fine. Dean can look after our clothes.’ You turned away, pulling your shirt over your head, leaving on the bikini top you’d stolen that morning. Sam’s eyes were fixed on the smooth expanse of your back, as Dean nudged him.

‘Skinny dipping with a mermaid,’ he pulled a ridiculous face as Sam scowled. ‘It’s like a porno come to life.’

‘Shut up, Dean.’


	3. Part 3

 

Sam’s teeth were chattering like crazy within two minutes of entering the water. You’d gone on ahead, checking the immediate area so he was safe, before returning to the boat to find Sam in his boxers, practically cuddling himself in the water as he kicked his feet to stay afloat.

‘You okay?’ You asked, circling him lazily, your tail making a soft current in the water around him. ‘It’s not that cold.’

‘It’s f-f-freezing,’ he replied, almost scowling at you. It was intended to sound angry, you were sure, but mostly he came off as adorable. Pausing in your circling, you came in close, your covered breasts pressing against his firm bare chest. ‘What are you doing?’

‘Warming you up.’ You grinned, cupping his face in your hands. Leaning in, you pressed your lips to his, using your tongue to pry his lips open. He was instantly pliable in your hands and moaned into your mouth, as you focused on using the gifts you had to warm him up. His body reacted to you, and his hands left his sides to pull you closer.

A shout interrupted you, and you broke away from Sam, scowling up at Dean’s face hovering over the side of the boat.

‘How about less groping, more swimming?’

Sam looked up, his scowl mirroring yours. ‘Shut up.’ Dean poked his tongue out petulantly, as you flipped him off.

‘I was warming him up,’ you spat, looking back to Sam. ‘Perk to being me - I can pass enriched air to you, makes it easier for you to breathe, and also, warms your body temperature a little closer to normal. I know it’s cold out here.’

Sam gave a half smile, his hands still on your scaled waist. ‘You know, you’re pretty distracting.’ His thumb moved along your hip where skin met scale. It was sensitive and ticklish, and you sucked in a breath, closing your eyes for a second. ‘And that’s going to get us lectured.’ He pulled his hand away and you had to bite back a whimper of disappointment, opening your eyes to see him looking up at his brother’s disapproving face.

‘Well, let’s get swimming.’ You flicked your tail, moving a little way away from him and turning your back. ‘Stay close.’ He nodded, even though you couldn’t see, and started to follow. It was difficult to keep a slow pace, but Sam wasn’t a bad swimmer, and kept up to less than a body length behind you. His movement in the water rippled along your skin, and you had to stamp down the thoughts in your head, Sam’s mostly naked form inspiring arousing thoughts that had no place for what you were doing.

‘This the cave?’ Sam yelled, gasping in the water as the pair of you came up to a rocky outcrop with a dark mouth. You turned, swimming on your back to look at him.

‘Yep. You doin’ okay?’ He gave you a thumbs up before propelling himself forwards again, and you turned, heading into the cave mouth, the slam of the water against the walls echoing in the dark space. You paused to allow him to catch up before turning and finding your path blocked by a large floating object bobbing on the waves. As you realised what it was, you covered your mouth to prevent your terrified cry giving you away.

Sam's arms came around you, dragging you backwards against his solid chest as you closed your eyes, unable to stop seeing the dead sunken eyes and shrivelled face of the long dead woman in the water.

‘It's okay, you're fine, I got ya.’ Sam's comforting words made you turn and you felt a hand combing through your tangled locks whilst you hid your face in the crook of his neck. ‘Never dealt with dead bodies before, I take it?’

You looked up at him, tears in your eyes as you shook your head. ‘No. I haven't. That's horrible.’

Sam's mouth set into a thin line. ‘She fits the description of the second missing vic. Looks like this is the right place.’ He kept his hands on you as he moved past, using the momentum of the water to float the corpse out towards the cave mouth. ‘Dean will pick her out. Get her back to land where she can be buried.’

‘How can you be so calm?’ You gaped at him, marvelling at his demeanour. ‘I mean, you barely flinched at me being a mermaid, now you're just casually pushing a corpse along so your brother can pick her out the sea?’

‘See a lot of crazy in my line of work. You're the least of it.’ He smiled, pushing your hair out of your eyes, his thumb stroking your cheek. ‘We can turn back-’

‘No. No, we have a job to do.’ Your expression was full of grim determination as you shuddered, hoping there were no more corpses ahead. ‘I said I could do this. I'm fine.’

Sam's eyes raked over you before he nodded. ‘Okay then. Looks like the back of the cave is up ahead. Maybe we should dive?’

‘How long can you hold your breath?’ You asked, and Sam smirked.

‘You want the dirty answer or the straight one?’ He chuckled as you splashed water at him. ‘I'm just breaking the tension. Uh, two minutes or so?’

You frowned, knowing that was a pretty good time but not enough. ‘Take my hand.’ Sam frowned before you grabbed his fingers, lacing them through yours. ‘If you need to breathe, squeeze.’ 

He nodded and you smiled a little, sinking down into the water, Sam's hand held firmly in yours. The water current was weak at the surface but you held on tightly as it grew stronger further down.

Debris littered the rocky floor of the cavern, including spots where it looks like Sedna had held her captives. You knew she had certain powers, like controlling the water, and maybe the weather, but this seemed like she had the ability to keep her victims alive underwater. Obviously it surpassed your ability to pass oxygen on.

‘Shit.’

Sam tugged at your arm and you realised, somewhat belatedly, that he couldn't talk.

‘She's gone further down,’ you explained, frowning. ‘I don't know how much of the pressure you can take.’ He nodded, pointing to the surface. ‘Good idea. You go back up and I'll come back to you in a minute.’ You pulled him close, holding his face as you pressed your mouth to his, making sure he could make it back to the surface. Sam's hands held you closer still, the life giving action becoming more intense as he tongue pushed against yours. His arousal was evident against your belly through his boxers and you pulled away, feeling a hot blush on your cheeks. ‘Go,’ you scolded and he grinned, before releasing you and kicking his way to the surface. 

Turning away, you swam further down, stopping when you caught a glimpse of a long, eel-like tail. Following it, you quickly found yourself propelled back by an unexpected current, and you fought against it, failing miserably. 

_ ‘Stupid merchild. Your family did not face me and survive, what makes you think you can?’ _

‘You're an evil old sea hag. Come out and face me.’ Your voice didn't carry very well in the water but you knew she could see and hear you, even if you couldn't lay eyes on her.

A distorted laugh reached you and you tried to squint into the darkness.  _ ‘The line is thin between bravery and stupidity, little one. You betray your kin, your gods by bringing those hunters here.’ _

‘You're killing people. I can't let that carry on.’

Another chilling cackle spread through the water.  _ ‘Do not delude yourself, child. I take what I am owed. And I take what I wish.’  _ The water grew colder around you, the pressure increasing as Sedna kept laughing.  _ ‘Watch your hunters run like the prey they are.’ _

Thunder crashed overhead and your eyes widened in panic. Obviously the goddess’ powers were not exaggerated as lightning flashed above the surface of the water. ‘Sam.’

Leaving the creatures laughter behind, you pushed upwards, breaking the surface with a splash. Sam was clinging to a jagged rock as the water swirled around him.

‘Y/N! What the hell is happening?!’ His yell was mostly swallowed by the wind howling through the air and you turned away, quickly swimming to the mouth of the cave. The boat was leaving and you couldn't go after it, not without leaving Sam to die. Turning back, you swam into the cavern, grabbing him and hauling him with you through the water. Lightning crashed again and the water churned more and more, rising up through the cavern. Sam clung to you, but you weren't sure if it was through fear of what was happening or concern for your well being. ‘What do we do?’

You scrambled for an answer, knowing that swimming out of the cave into open water was a bad idea. You looked around, spotting a ledge about six foot above the water.

‘Do you trust me?’ Your voice was a shout above the water and Sam's eyes met yours as you saw him contemplating the question. Slowly, he nodded and you smiled, pointing to the ledge. ‘I'm gonna have to throw you. It might hurt.’

He grinned despite the situation. ‘You can kiss it better.’

You laughed, before catching him unawares, pushing him backwards and launching him towards the ledge. He flailed in midair, soaked fingers scrabbling for the edge and for a split second, you waited for him to fall backwards into the water, holding your breath. His arms flexed and he almost snarled as he managed to drag himself upwards, hauling himself onto the ledge, panting as he came to a rest.

‘Need a hand?’

‘Might do.’

You ducked down, swimming under the surface a few metres before launching yourself through the water. Your aim was off and you thrust your arms out, closing your eyes as you waited to impact the water or the wall. A cry of shock left you as Sam's strong hands grabbed you almost painfully, dragging you up towards him. You landed heavily on his chest, gasping for air as your body rippled and changed. Using your newly reformed knees, you climbed onto all fours, looking back over the ledge.

‘Okay. So…’ Sam was still panting. ‘This isn't good. Also, you're  _ very _ naked.’

You looked down, gasping at your nudity. As you went to cover yourself, a wave smashed into the wall and you rolled back, expecting to hit the back wall. When you slid into an open passageway, you frowned, looking up.

‘Another cave?’ Sam crouched, moving towards the slim crack in the rocks. ‘Looks dry in there. How long do you think this storm will last?’

‘How long is a squid’s tentacles?’ You sighed, leaning against the rock. Sam reached over, taking your hand gently. ‘This is my fault.’

He raised an eyebrow. ‘I don't see how. Come on.’ You hesitated, before following him through the hole in the rocks. It was slightly warmer the further into the crevice you went, and the storm behind you grew more and more distant. Sam was already doubled open, and your brow creased as you panicked that there might not be an end to the passageway. ‘Wow, look at this.’

His hold on your hand loosened a little as he went on ahead a little. The passage opened up into a second set of caverns, and your mouth dropped open as you looked up, seeing that it was at least twelve feet high. Sam straightened, looking around before looking back to you, his eyes averting when he remembered you were still naked.

‘We have to get back to shore,’ you whispered, but Sam shook his head.

‘We can’t go anywhere with that storm raging. If Sedna is controlling it, she could be doing this for hours.’ Sam’s face softened as he tugged you close. ‘You’re freezing.’

‘Harder to control my body temperature in this form.’ You shrugged, not resisting as he pulled you close. ‘Not like we have any blankets or clothing to warm up, and it looks like the boat owner turned around and left us.’

‘Dean will come back for us.’

‘If we can just swim out of the cave, I can get you back to shore when...when the storm is done, we just -’

‘Y/N?’ Sam’s voice was breathy as he spoke, his large hand cupping your cheek and tilting your head upwards. ‘This is so inappropriate.’ His breath was hot on your lips as he pulled you flush against his body, water from his skin mingling with your. Patches of scale appeared where water ran over your legs, and he smiled as he pressed his nose against yours. ‘I can’t seem to care.’

You whined a little as he nipped at your bottom lip. ‘Sam -’

Your voice was cut off as he claimed your mouth with his. His lips were soft and warm, and you threw your arms around his neck, clinging to him as his large hands grabbed your rounded ass. It reminded you of how naked you were, and arousal blossomed between your thighs.

‘Is this…’ you gasped, curling your fingers in the wet hair at the nape of his neck. ‘Is this the best place for this?’

Sam pulled back, looking around the cave. ‘Better than the thoughts I was having of just taking you on that boat earlier. I don’t think Dean would have approved.’ He grinned. ‘You’ve had my attention since the second you walked onto that pier.’

‘I was trying to be sexy and mysterious,’ you admonished. ‘You ruined that with your hero routine.’

He shrugged, capturing your mouth once more, the kiss deeper than the last, his tongue stroking against yours. When he broke away this time, his eyes were lust blown, his bare chest heaving, and his cock lay heavy against your belly. ‘Would you have rather never met me?’

You smiled, tilted your head to the side. ‘Oh, don’t say things like that, Sam.’ You pushed against his chest, jerking your chin up. ‘Maybe you should lay down, you look a little peaky.’

‘Do I now? You gonna be nursemaid?’ Sam let you push him backwards, your fingers dragging down his chest to pluck at the waistband of his boxers. He groaned as your fingers brushed against the tip of his swollen length, and your grin widened.

‘I prefer to be on top.’

‘I’ll bet.’ Sam grunted as you pushed him again, and he fell backwards, landing on his ass as you dropped down onto him, crawling over his large body. ‘Take that bikini top off. Wanna see all of you.’ You reached behind, untying the top, flinging it away as Sam seized the opportunity to slide his hand between your thighs. ‘Fuck, you’re wet. That for me?’

You whimpered loudly, grinding down onto his thick fingers as he spread you open. His name left your lips as he used his other hand to hold you upright, the muscles of his arm bulging as he worked his fingers deeper into your slick pussy. The noises you made bounced off the walls of the cave, and Sam grinned in satisfaction as you arched upwards, crying out.

‘Come here -’ He grunted as he pulled you down, withdrawing his fingers from you, his hips jerking upwards as your bare cunt brushed against his covered cock. You lowered your mouth to his nipple, circling your tongue around it and smiling coyly when he tensed and groaned at the sensation. ‘Y/N, fuck, that feels so good.’

You raised your head, rubbing against him, before pressing your lips to his. Your fingers reached up, tangling in his thick locks and tugging, pleasantly surprised at the moan he let go, feeling it vibrate against your tongue. ‘Nipples and hair pulling? You’re a kinky kind of guy, Sam Winchester.’

He smirked. ‘You haven’t seen anything yet.’ His hands pulled you up, so you were straddling his waist, giving him access to your breasts as he yanked his soaked boxers off. Stretching his neck, he licked at one nipple, then the other, pausing to suckle hard at the tender flesh and you cried out. His fingers drifted over your thighs, and you wiggled down, just enough for the tip of his cock to brush against your entrance. ‘You want this?’ He asked, gasping for air as he pulled away from your breasts. You nodded, smashing your mouth to his as you rotated your hips against him, eager to feel the thick length of his cock stretching you out.

‘Sam, please. Want you so bad…’ Sam groaned at your pleading words, pushing his cock through your pussy lips, feeling you shudder in pleasure. ‘Need more.’

He slowly eased into you, inch by inch and you clung to his shoulders, gasping into his mouth as he slid home, his cock thicker and longer than anything you’d felt before. He didn’t stop until his hips were flush with yours, and you were panting and mewling his name. Without moving, he pushed you up far enough to look into your eyes, smiling seductively.

‘Sit up for me, baby. Wanna see you ride me.’

You moaned as you moved your hips experimentally, awed at the sheer size of his cock, feeling more pressure at your core than you’d ever felt in your life. ‘You okay there?’ You asked, knowing it couldn’t be comfortable laying on the rock floor. ‘We can -’

He cut you off, his thumb covering your lips. ‘Just sit up. I’m fine. I wanna see.’

Slowly, you obeyed, sitting up and crying out as his cock twitched hard inside you, the sheer size of him sending every single nerve into pleasure overdrive. ‘Sam…’ you mewled loudly, using your hands to brace yourself against his thighs. His fingers moved from your legs up to your lower belly, and he chuckled, sending a cacophony of sensation through your body where you were connected.

‘Look at that,’ he muttered, his fingers running over your skin and you arched, letting his name leave your lips again. ‘Can see where I’m inside you, sweetheart. So fucking tight and wet for me. Exactly how I thought you’d feel.’

‘Fuck, you’re…’ You brought your left hand round to feel where he held your belly, just as he thrust up into you, the thick tip of his cock pushing your stomach outwards. ‘So fucking big, Sam, I’m...I’m not gonna last.’

He nodded, moving his hands to lift you up almost all the way off of his cock. You weren’t as weak as a human woman would be but the way Sam manhandled you was so erotic, it could have jumped straight out of a porno, and as he slammed you back down onto his cock, feeling like he might break you in the best way possible, you screamed in pleasure.

Over and over, he repeated the action, as you clung on for the ride, eventually fighting back against his movements, making everything more intense. The storm was a distant memory as you used your thighs to pin him down, forcing him to roll you underneath his strong body. Sam was all too eager for your touch, letting you tug on his long hair as he pounded you into the rock floor so hard, you knew there’d be bruises, possibly scratches on your back. He lifted your right leg, seizing your mouth again as he changed the angle, and you screamed into his mouth as he slammed his cock straight into your sweet spot, sending you flying into a white-out abyss that left you quivering around him. 

‘Sam...Sam...fuck, I can’t -’

‘I know, I got ya, I’m close, sweetheart, just...fuck, squeeze me just like that,’ he kept talking, kept urging you on as your limbs grew heavy and tired, all thoughts of the cold and the danger going right out of your head as you felt him swell and pulse and finally spill into you, his come hot and thick as it spilled out around his cock.

Both of you clung to each other, Sam’s mouth taking yours in a final deep kiss, as you twisted your fingers in his hair, desperate to never let go. The warmth of his body surrounded you, and when he withdrew from your pussy, he pulled you close, letting you curl into his larger frame.

‘I got you.’ He whispered, kissing your temple as the pair of you came down from the high you’d found together. ‘I promise.’

You smiled, tucking your head underneath his chin, and for a few moments, neither of you moved or spoke. Slowly, you realised that the storm had stopped, and after listening for a few seconds, you sat up, frowning.

‘The storm stopped.’

Sam sat up too, reaching for his boxers. ‘I’ll go check.’

‘You can’t go alone.’ You pouted, grabbing his arm as he stood up. ‘I’ll come with you.’

‘I have boxers at least. You don’t have a whole lot.’ He grinned, gesturing to your naked body. ‘I’m only gonna be a second. If the storm has gone, we can swim back to shore.’

‘It’s a long swim.’ You warned, and Sam chuckled, bending to kiss you again.

‘We’ll make it.’ He turned, disappearing through the cave entrance, and you moved forward, listening intently. There was a loud splash, and you frowned, squeezing through the gap. ‘Y/N?’ Sam’s voice was tight, almost like he was being strangled.

‘Sam?’

_ ‘Call her out, Samuel. Let her see.’ _

‘Shit,’ you cursed loudly, rushing through the slit in the rock so fast you caught yourself, leaving small cuts and welts on your arms. As you rushed out onto the ledge, you saw the calm sea, and Sam was hanging from the edge, a thick tentacle like appendage wrapped around his neck. ‘Sam?’

_ ‘Such potential. Even before he met you, little merchild, he was destined for such greatness. A little old for my taste, but he’ll sustain me for a century with everything he has held inside.’ _

‘Let him go.’ You tried to sound fearless, but terror was curling into the pit of your stomach and you reached out, as Sam did the same, fingers almost touching.

_ ‘I thank you for this gift, child.’ _ Sedna’s voice was mocking.  _ ‘Such a gift it is, the potential you gave him.’ _ Sam’s fingers were so close, and you lunged, only for him to be dragged down over the ledge, his anguished shout only echoed by your petrified scream.

Without stopping to think, you threw yourself into the sea, your natural form taking over instantly, and you swam hard and fast…

...Only to find darkness.

Sedna was gone. And she had Sam.


	4. Part 4

 

‘Y/N!’ Dean shouted your name as you breached the surface by the pier, gasping through your tears. Almost immediately, he saw his brother was missing, and a dark cloud descended on his face. ‘Where the hell is Sam?’ His hand was automatically going for his gun and you held up both arms, shaking your head as more tears threatened to erupt.

‘She took him, Sedna, she grabbed him and I couldn’t stop her.’

Dean’s face fell, his hand pausing as he realised the depth of your words. ‘The sea monster got him? Is he…’

You shook your head, moving around to the lower side of the pier. The storm was still rumbling out to sea, the piers mostly deserted because of the heavy rain. ‘He’s alive, I can go back and find him, but, I can’t, I can’t do it alone.’

‘I never should have let him go with you.’ Dean growled, finally unholstering his gun and pointing it down at you in the water. You didn’t even fight the tears letting them fall. ‘You’re just as bad as that other thing out there. You’re not human.’

‘Dean, I -’

‘Shut up! My brother is gone because of you.’

You slammed a hand down into the water, making a large splash and feeling several cruising pods of fish scatter at the movement. Your tail twitched in agitation and you felt like screaming at him. ‘You think I don’t know that? The second your brother saw me...I shouldn’t have let it get this far. But you wouldn’t just  _ leave _ . You had to stay and I couldn’t help...I couldn’t stop  _ feeling _ this way -’

Dean scoffed angrily. ‘What, you telling me that you’re in love with him? After a day?’

‘I don’t work like you do, Dean,’ you spat, narrowing your eyes. ‘Something about Sam drew me in and I couldn’t stop it. I should have, I know that but…’ You wiped at your eyes uselessly, knowing you were just wiping water away with more water. ‘Look, I can’t save him alone. I need your help.’

He stared at you, his mouth set in a thin line before he shook his head. ‘I can’t believe I’m doing this. Can you get up here?’

You looked around, your bottom lip shaking as you realised it was too public. ‘No, too many people. I’ll either draw a crowd or get arrested for public indecency.’

Dean snorted, putting his gun back in its holster. ‘Well, I haven’t had any luck getting a boat. They all shut down because of the storm. The guy you hired is lucky I didn’t knock him out. He wasn’t too happy that I threatened him either.’

‘I’ll have to find a way out where no one can see. Shouldn’t take me too long.’

He nodded. ‘I’ll go back to the hotel. We still need to find the weapon to kill her, but I’ve got a friend I can call, he might be able to help.’ He peered down at you, scowling. ‘We find Sam, and you’re gone, you got it? I don’t care what kind of  _ connection _ you feel with my brother, I’m holding you personally responsible for his safety.’

You swallowed down the anguish in your throat, not responding to his words, watching him move off. With a shaky sigh, you dived back under, heading along the piers. It wasn’t as busy as it could be, but with every push towards the shore, something pulled at you, beckoning you to the open ocean. You knew it was Sam, whatever you’d forged in that cave with him had cemented itself deep in your soul, and you fought back the urge to go find him alone. You had no weapon, and no way to defeat Sedna, which would ultimately lead to his death and yours.

Finally, you found a quiet spot, a pier built solely for car parks. It was a fight to climb up the thick ballasts as your legs gave way to tail, even harder to do so without being spotted, but you somehow managed it. Weaving through the cars, you stopped when you saw one with luggage in the back, and decided that petty misdemeanour was required to save Sam. Ten minutes later, you were strolling out of the car park with a pair of exceptionally baggy jeans and a Grateful Dead shirt that was three sizes too big.

You headed straight for the hotel, avoiding crowds, and trying not to take any notice of your bare feet on the warm sidewalk, although you took care not to cut yourself on anything that had been dropped by a tourist. Your stomach rumbled as you walked, reminding you that you hadn’t eaten, and it took some effort to quickly steal some food from outside a shop, keeping your speed up as you headed for Dean’s location.

When you got there, he didn’t seem at all happy to see you, and he wasn’t alone.

‘This is Castiel.’ Dean muttered, standing aside as you walked into his hotel room. ‘He’s…’

‘An angel?’ Your eyes widened. You’d heard of the celestial beings, but you’d never seen one in person.

‘She is merfolk.’ Castiel stood up, a small smile pulling at his lips as he cocked his head to the side, almost examining you. ‘Dean did not mention this.’

‘I didn’t think it was important.’ Dean shut the door, using more force than necessary as you flinched. ‘Anyway, Sam got taken by some sea monster, and we need help to find him.’

‘It’s Sedna. The goddess.’ You explained, and Castiel frowned, looking away from both of you. ‘She took him, and I know she’s still in the bay, but I can’t…’

The angel’s head snapped up to look at you. ‘You can feel Sam. There is a connection between you.’ He moved closer, holding two fingers up to your forehead. ‘Yes. It’s new, but it’s there, and it’s our best chance of saving your brother.’ Cas smiled as he drew his fingers away. ‘You can still swim, yes?’

‘Yeah, I can. But we need the weapon to stop Sedna. A fresh water blade, I don’t know how to get one of those.’

‘I can obtain that for you. But you cannot go alone.’

Dean cleared his throat. ‘Fancy conjuring us up a boat, Cas? We’d be real grateful.’

Castiel chuckled. ‘A boat would not be of any help here. But I can do something else that may assist. I can temporarily give you the necessary organs to swim underwater with Y/N.’ Dean’s eyes bulged as your jaw hit the floor. ‘It’s quite a simple transition - your DNA is basically identical, but your species evolution split paths a millenia ago.’

‘You’re...you’re gonna make me a mermaid?’ Dean didn’t sound the slightest bit excited by the idea.

‘A merman.’ Castiel corrected, nodding as he shed his trenchcoat. ‘Now, this could cause some discomfort, but you won’t notice any real change until you enter the water.’ He reached out and Dean flinched back from him, looking a little cornered. ‘Dean, this is essential to save Sam.’

It seemed to be the magic words required and Dean’s shoulders dropped. You watched curiously as the angel’s hand came to rest on the hunter’s chest, and Dean hissed loudly as light seemed to pour from Castiel’s fingers. The angel’s face was screwed up in concentration and after a few seconds, Dean jumped backwards, falling to his butt as Cas watched, a little bemused.

You felt it then, an strange extra sense perking up that you hadn’t felt since you’d lost your family - a feeling of kin. Dean was practically writhing on the floor as his body changed, and Castiel looked over at you, shrugging.

‘He should be fine in a few moments. I will return momentarily with the weapon you need.’ You reached out, about to ask him to wait, but the shout fell on empty space, and you scowled, disliking the way he just disappeared. You dropped low to the floor and moved over to Dean, approaching him cautiously as he gave one final arch up off of the hideous purple carpet. He slumped into a pile on the floor, his eyes shut and everything about him still.

‘Dean?’

He jumped and gasped, taking a deep breath before coughing. You knew the second he tasted extra rich oxygen and bolted upright, his eyes wide as he looked at you. 

‘You okay?’

‘Yeah,’ he sucked in another breath, looking a little confused. ‘Just...breathing is, er, new? I guess.’

You smiled, offering a hand to help him to his feet as he checked himself over. ‘You’ll adjust. Four lungs. One set for air, one set for water. Your body will know what set to use when. It’s weird, I know…’

Dean frowned. ‘You’ve had this your whole life, this is...jeez, this is weird. Is your hearing always this sensitive?’ He winced, and you shrugged. ‘And there’s this weird like...is it a sixth sense? Like I know you’re there without...knowing...fuck!’ Castiel reappeared and Dean jumped out of his skin, before his entire body sagged in frustration.

‘The human body has approximately fifty two senses, so I do not know why they refer to them as six. And merfolk have twice that because of their species heritage.’ He handed you a thick slab of pointed rock. ‘That is the weapon you need. A blade forged from freshwater.’

You hefted it in your hand, pulling a face at it. ‘It’s a rock, Cas.’

Dean took it off of you, examining the point. ‘We’re gonna have to get fucking close to use this.’ He scowled, looking over at the angel. ‘No projectiles available?’

‘We’ll get close enough,’ you grimaced, taking the rock back. ‘We need to move. Before she starts hurting Sam.’

*****

It was dark out as you headed down to the beach, with Dean trailing behind you. Castiel had left, insisting he was not of any use to you under the waves, and you’d reluctantly agreed. He had told you to call if there was anything else you needed, and flown away, leaving you with a grumpy Dean, who did not look too happy about throwing himself into the waves.

As you stripped off on the darkened beach, the silver sand highlighting the both of you as you headed for the water, Dean studiously avoided looking at you. He kept his boxers on, leaving his clothes in one pile, whilst you left yours in a messy trail down the beach. You threw yourself into the water head first, twisting under the black surface and coming back up, flicking your tail as you waited for Dean, weapon in hand.

He stood on the water’s edge, looking nervous as hell, his toes curling away from the ocean as it lapped at the sand.

‘Come on, Dean.’ You groaned loudly, and he scowled up at you, before throwing himself into the water beside you, making a less than graceful splash and coming up gasping for air. ‘Relax or you’ll pull something.’ You ordered, grabbing his shoulder. ‘Let your instinct take over.’

‘I don’t have instincts,’ he growled back, pushing you off. He bobbed in the water, and you rolled your eyes, sinking down below the surface, seeing his long emerald green tail flowing out behind him. It was kind of pretty, but at the same time, you couldn’t help but wonder what colour Sam’s tail would be.

Dean turned, submerging himself fully as he tested the power of his new appendages, looking a little excited as he swam in a straight line down. ‘This is amazing!’ He yelled, before stopping and turning back to you. ‘Wait, we can talk underwater.’

You laughed loudly, shaking your head as you swam past him. ‘Yes, now move it.’

He nodded, following dutifully as you sped through the water, surprised that he adapted so quickly and literally kept on your tail the whole time. ‘Is she down here?’

‘I can feel Sam,’ you replied, heading in the direction you felt the pull guiding you. Dean was at your side now, looking over at you as you swam with absolute focus.

‘I feel him too,’ he said, a strange look on his face.

‘Merfolk can feel their family. They can feel other members of the species. You’re zeroing in on Sam because he’s your brother, your family.’

‘And you?’ Dean asked, and you didn’t answer, trying not to think of the implications.  _ You could feel Sam because he was your mate. _ A sigh left your throat as you kept going, looking up to see a pod of whales swimming near the surface. Their song echoed through the water and Dean had an expression of awe on his face as he heard it. ‘That’s amazing.’

You nodded. ‘Wish I could show you more. You and Sam. But we have to...we have to find him before she -’ You pulled up, frowning as you looked towards the endless black in front of you. ‘Wait.’

‘What?’

‘Down.’ You looked below your tail, seeing even darker depths. ‘It’s pulling me down. What do you feel?’

‘The same, I think? I don’t know. It’s all new to me.’ Dean looked a little frustrated, and then you heard it, above the whale song. A cackle, a familiar cackle at that, and your blood boiled. ‘What was that?’

‘The sea hag,’ you spat, moving your tail to propel yourself down into the depths.

The water seemed to grow thicker with the pressure the further down you swam, and you could hear Dean mumbling his concerns at your side. He kept pace, both your tails leaving a current in the water behind you as you descended. The cackling didn’t stop, and the sound of it made fear cascade down your spine as you drew closer.

‘We’re close.’ You said, pulling up into a stop, Dean following suit. ‘She’s feeding.’

‘On Sam?’

‘I don’t think so.’ You moved a little further forward, seeing the ocean floor below you, noticing the area was devoid of life. ‘There’s not a single fish here.’

‘That normal?’ Dean asked, and you shook your head. ‘Oh.’

You squinted, trying to focus through the blackness. It was rare for any merfolk to venture this deep, with the dangers of the open sea, and it was so dark, it was difficult to focus. ‘There.’ You thrust your arm out, pointing to an enclosed pit. ‘There’s a light. It’s faint, but that must be where she is.’ You flicked your tail, pushing yourself downwards, feeling Dean disturb the water as he followed.

The cackling ceased as you both drew closer to the light source, following it into a wide open cavern. There were bones littered across the floor, dug into the sand where plants had once grown, but now lay dead and decaying. Obviously Sedna’s presence had a more profound effect that you realised. You motioned to Dean to keep quiet, slowing your movements as you approached a thin rock corridor.

_ ‘So many ideas, this one has. Will sustain me for years.’ _ The sea goddess waltzed into view and you drew back at the first true sight of her. It was difficult to tell where the light was coming from but it was enough to show the thick rotten flesh that covered her almost-humanoid form. She had arms, but no hands, her limbs ended in slimy tentacles, with vicious claws at the tips. Her tail looked reminiscent of a merperson’s tail, except the scales were thicker, scarred and a sickly brown colour. Her face was contorted and swollen in boils, sharp teeth gnashing as she worked at her victim, a male in his late twenties. You could see he was already beyond saving, and you scanned the room for the rest. In one corner, still as if they were in suspended motion, the five remaining missing people were strung up in filthy looking old fishing net, including Sam.

Dean tensed behind you, and you reached out to stop him charging in, shaking your head at him. Sam’s eyes were closed, and he appeared unharmed, although there was a thick bruise around his neck where Sedna had grabbed him from the cave.

The monster turned, and you pulled yourself back before her one open eye caught you. She gave a loud snarl of satisfaction, and a few moments later, the dead body of the man she’d been feeding on floated out past your hiding place. Your face drained of colour as Dean looked on in horror, and you closed your eyes for a second, composing yourself.

Sam was in there, and you needed to save him and kill the monster. You gathered every ounce of courage you had, and peeked around the corner, only to come face to face with Sedna’s large open yellow eye, the putrid smell of her skin invading every pore you had. The sea hag’s tentacles whipped out, grabbing you and dragging you into the cavern, laughing loudly.

_ ‘Look who swam all the way down here for her sweet prince. And alone too.’ _

Dean pressed back against the wall, hoping she wouldn’t notice him, even as you gave a strangled cry, your tail catching on a rocky outcrop. You flung your hand out, dropping the rock blade before Sedna could see it, and it floated down to the ground, a few metres below. Dean’s eyes landed on the blade, and he swooped down to pick it up as you let a piercing yell loose.

‘Let me go!’

_ ‘So feisty, child.’ _ Sedna laughed, and you found yourself grabbing at the tentacle around your throat, struggling against her.  _ ‘I warned you.’ _

The tentacle contracted around your throat, and you dug your nails into the appendage, almost choking under the weight of her slimy flesh. Your fingers slipped, and you lashed out with your tail, managing to hit her. It didn’t seem to do much damage, and the disfigured goddess laughed loudly, turning to slam you against the wall. The nets holding the other victims seemed to grow, and your eyes rolled back as she deprived you of oxygen.

_ ‘His potential is astounding, as is yours. Like a fairy tale, love that transcends boundaries.’ _ Sedna leaned in, licking your cheek and humming as you felt the darkness overtaking your head.  _ ‘I’ll feed on both of you and you will sustain me for centuries to come. I can taste your power, little mermaid.’ _

‘Hey, Ursula.’ Dean’s voice was loud and echoed through the cave as your body went limp in the monster’s grasp. ‘Taste this.’

Sedna whirled around, her tentacle loosening from your neck, and you slumped down into the dark water, reaching the cavern floor just as Dean thrust the freshwater rock into the goddess’ blubber coated chest. It made a disgusting squelchy wet noise as he pushed it further in, the crunch of bone reverberating as Sedna screamed in fury. She batted Dean away, black inky blood surrounding her as he hit the cave wall with a thud, froth kicking up in the water around him as he recovered from the hit.

You shook away the darkness threading through your mind, looking up to see Dean pushing off of the wall, ready to attack the injured monster, as she snapped her jaws and flung tentacles towards him. He dodged the hits, and you saw the rock sticking from her chest, the black blood still spreading through the water.

‘Dean!’ Sedna turned at the sound of your voice, and you used your remaining strength to launch yourself upwards, grabbing onto her foul looking tail, grimacing at the feel. The movement exposed her chest, and Dean pushed away from the wall as Sedna tried to kick you off, spinning in the water and using his thick green tail to slam against the rock blade. It sank further in, with a sickening crunch, and the beast screamed, a sound that made both you and Dean cover your ears.

Her tentacles kept flailing, but were no longer reaching for anything as she shuddered and shook, her form almost collapsing in on itself. Her flesh began to melt, the boils sinking into her face as she tried to fight the inevitable. Dean swam over to you, helping you off of the floor.

A keening wail erupted from the goddess as she shrivelled away, and you clung to Dean, as she finally withered into nothing. The black ink-like blood in the water sank down, disappearing into the thick sand on the floor of the cavern. Dean held you up, before his attention turned to Sam and the other victims.

‘How do we get them out of here?’

You let go of him, swimming over to Sam and reaching out to touch his face. ‘They’re cold. I don’t know how long her magic will last now she’s dead.’

Dean frowned, picking at the net holding them. ‘We’re pretty strong, right?’

‘In this form.’ You replied, seeing the cogs whirring in his head. ‘You think we can use the net.’

‘They’re pretty secure in here. We could use it like a stretcher?’

‘It’s pretty much our only option. If they wake up down here…we wouldn’t be able to get them to the surface before they drowned.’ You saw the fingers of one of the victims twitch. ‘We need to move. Like, now.’

Dean nodded, and the pair of you quickly pulled the netting from the wall, securing each victim and Sam, until you were both confident you could carry them safely. It was a squeeze to get them out of the cavern, and as you started the swim upwards.

Your arms were exhausted, and you could feel the bruises from your encounter with Sedna beginning to blossom. Your tail was aching, and you wanted nothing more than to find somewhere soft to sleep for a week, preferably with an awake and unharmed Sam. It was doubtful Dean would be happy with that course of action, but you weren’t about to bring it up in conversation.

‘I was wrong.’ Dean suddenly blurted, less than ten metres from where the moon lit up the surface of the water. ‘I mean, it’s freaky, having a tail. But I can see what’s good about it. You’re…I shouldn’t have said what I said. You’re not a monster.’

‘I guess that’s something.’ You smiled as you glanced back. ‘Let’s just focus on saving these people, huh? And Sam.’

‘Yeah.’ He nodded, and a few moments later, you broke the surface. The fresh air hit you like a ton of bricks, and you hauled the net upwards, seeing the spell break as the captives breathed in fresh air. Sam’s eyes opened and you felt relief flood you. ‘Sam!’ Dean’s voice rang out across the water, and you watched as the elder brother embraced the younger. The others were beginning to stir, panic taking hold as they realised they were in the middle of the ocean.

‘Hey, hey!’ You tried to raise your voice, but the four humans were too freaked out to pay attention. ‘Guys, you gotta calm down!’ The youngest victim, the twelve year old, started to sob, and you focused on her, grabbing her by the shoulders. ‘You’re gonna be fine. We got you out, and we’re gonna get you home, okay?’

‘I-I’m so cold –‘ She replied, teeth chattering, and you looked at Dean helplessly.

‘Cas, conjuring up a boat would be real helpful now?’ The green eyed hunter muttered, glancing at his brother. ‘I did mention that the first time.’ Sam gave him a funny look.

‘Dean…’ The younger brother looked down, frowning at his brother. ‘You’re….is that…’ The sound of an engine in the distance caught your attention and you turned, seeing a small boat coming towards the spot you and the others were floating. ‘Dude, you have a tail.’

You yelled loudly, distracting everyone, and a light flashed out from the boat, in your direction. Realising the truth of the situation, you splashed water at Dean to get his focus. ‘We can’t be here,’ you hissed, and he frowned, then realised exactly why you and he had to leave. Finding a bunch of missing persons in the middle of the bay was one thing; finding them with merfolk was completely different and a lot harder to explain.

Sam reached for your arm, grabbing you as you made to leave. ‘Y/N, I don’t unders-’

‘No time, Sam.’ Dean growled, clapping his brother on the shoulder. ‘Make up what you need to. We’ll meet you back at the hotel, yeah?’ Sam nodded mutely, as you gave him an apologetic look, following Dean down under the water as the boat drew closer. Once at a safe distance, you watched from below, seeing each human being plucked out of the water.

The boat moved off, and you looked at Dean, who nodded. ‘Let’s go,’ you whispered, making towards shore. Both of you swam silently, until the sound of the city grew louder and the ocean floor came up to meet you.

‘For what it’s worth…’ Dean started, as you made it onto the beach into the sand, waiting for the water to drip from your tail. Your legs started to form and you noticed that no one had stolen the clothes you and he had dumped, which was a relief. ‘You make my brother happy? You got my blessing.’

You tried not to smile at his hesitant words, knowing that it wasn’t an easy situation. Laying claim to Sam was easy - making your relationship work when you belonged in the sea and could die without it? Not so much. ‘Let’s just get back to the hotel and have Castiel take the mojo off you.’

Dean looked down at his drying body, shaking out his legs as soon as they were fully formed. ‘I dunno. Could be nice to spend a weekend as a merman. I mean, imagine the chicks I could get.’

You couldn’t help rolling your eyes as you pulled on your discarded clothes, throwing his pile at him. Dean grinned and dressed quickly, trying to save his modesty. As soon as he was done, the both of you moved up the beach, noticing a little commotion down on the pier. Drawing closer, you saw police cars and ambulances, surrounding the boat that had picked up Sam and the others.

‘We need to stay back.’ Dean gripped your arm, pulling you backwards as you frowned. ‘Sam will take care of it.’

The scene continued as you and Dean watched, keeping in the shadows of the storefronts, as the sun started to rise. You yawned widely as the police began to leave the area, and Dean tugged at your shirt.

‘When did you last sleep?’

You laughed. ‘Sleep? What’s that?’

‘Amen, sister.’ Dean grinned, jerking his head in the direction of the hotel. ‘How about we go get some shut eye and wait for Sam.’

*****

As it turned out, you were more tired than you’d ever felt in your life, after three days of too much excitement and not enough rest. Dean had suggested food, but you’d gone straight for Sam’s bed and curled up in his blankets, asleep within moments.

Waking up with a large warm body next to you was unexpected but not entirely unwelcome. You turned in Sam’s hold, looking up at him with a tired, but happy expression.

‘Hey,’ he whispered, one large hand cupping your face. ‘Hope this is okay. Dean doesn’t like spooning.’ His joke made you giggle and you couldn’t stop your body arching into his, your lips seeking out a soft kiss from his warm mouth. ‘Hmmm, that was exactly the reaction I was looking for.’

‘I was so worried,’ you admitted, fingers curling in his thin t-shirt. 

‘Worried enough that Castiel had to turn my brother into a mer...person?’ Sam raised an eyebrow and you bit your lip. ‘He’s back to normal now, by the way. You’ve been out for like, twelve hours.’

You looked down, sighing. ‘Hadn’t had a whole lot of sleep.’

‘I guessed.’ He frowned, his thumb stroking over your cheek. ‘I think we...er, need to talk? I mean, about what happened. Between us. Sea monster I get, she’s dead, so not a problem. But you...I keep feeling this weird...connection. Am I going crazy?’

A laugh spilled from your lips and you shook your head. ‘Not crazy. I didn’t think you’d feel it too.’

‘Feel what?’

‘I’m not human, Sam. When we...when we…’

‘Had sex?’

You blushed. ‘I didn’t wanna sound too crude. But when we...did that, I sort of, may have imprinted on you?’ You rushed the words out, not waiting for him to reply. ‘It was my fault she took you. And I don’t blame you if you wanna leave and not look back, I would totally understand -’

He silenced you with a deep kiss, his hands grabbing at your waist to pull you closer, flush against his body. ‘If Dean wasn’t asleep in the next bed, I would have you right here. I’d show you that leaving you behind is the last thing on my mind.’

A whimper left you, and you smiled, feeling tears well up in your eyes. ‘Sam, I can’t leave the bay. I mean, I could, but I’m a mermaid, and I have to be close to the sea. I can’t travel with you, or hunt with you, or...this would only end badly.’ You chewed on your lip, letting your eyes lock with his. ‘Unless…’

Sam frowned. ‘Unless what?’

‘I don’t have anything left here, Sam. My family are gone. There’s no pod round here to swim with, and I don’t think I could stand being left behind.’ You sucked in a breath. ‘I can ask Cas...to do what he did to Dean but in reverse. To me. Make me human.’

‘Do you think he can do that?’ Sam asked, pressing his forehead against yours. ‘Would you really give that up for me?’

You smiled widely. ‘Sam, I don’t think there’s a whole lot I wouldn’t give up for you. Since the second I laid eyes on you, I knew my life was gonna change. And I think...love is worth the risk, right?’

Sam smiled, kissing you again, and you knew his answer.


End file.
